In 1980, Sinn et. al. found that with MAO as the cocatalyst, Cp2ZrMe2 exhibited remarkable ability for the polymerization of olefin, thereby raising the upsurge of studies on metallocene catalysts, which, in the catalysis of ethylene polymerization, show high activity, favorable copolymerizing performance and narrow molecular weight distribution of polymers etc. Metallocene catalysts having Cs or Cl symmetry may catalyze the polymerization of propylene to obtain structure-controllable polypropylene (Angew. Chem. Int. Ed. Engl., 1995, 34, 1143; EP 37130 (1993); CA 119, 2507262 (1993)). In the late of 1980s, a bridge hydrazine-cyclopentadienyl ligand containing constrained geometry configurated semi-metallocene catalyst (CGC catalyst) was invented, which manifested exceedingly high activity in the catalysis of polymerization of propylene as well as copolymerization of ethylene and alpha-olefin (EP 416815 (1991); EP 420436 (1991); Chem. Rev., 2003, 103, 283.). In recent years, polyolefin catalysts having large p bond ligands have been rapidly developed. Other than typical transition metal complexes with cyclopentadiene and its derivatives as ligands, the application of another category of transition metal complexes containing coordinated heteroatom ligands such as oxygen, nitrogen etc. for the catalysis of olefin polymerization has been paid more and more attention to. For instance, U.S. Pat. No. 5,539,124 discloses a pyrrole ring containing transition metal catalyst, whose general formula is expressed as (L)m(Cp)qM(Y)n(B)p, wherein L is a ligand or mixture of ligands, one of which containing at least two fused rings with one being pyrrole ring; Cp is a group containing cyclopentadiene; two L ligands or one L and Cp may be bonded into a bridge; B is Lewis base; Y is selected from the groups consisting of halogens, C1˜C20 alkoxyl, C1˜C20 silicone, N(R1)2 or a mixture thereof, M is Ti or Zr; m is 1˜4, n is 0˜2, p is 0˜2, q is 0˜1 and m+n+q=4. The catalyst can be used to catalyze the polymerization of olefin, but has low catalytic activity. For instance, if MAO was as cocatalyst, dipyrrole zirconium dichloride had the catalytic activity only for 1.5 kg polyethylene/molar catalyst/hour under 1.0 MPa at 110° C. CN1169736A discloses a olefin polymerizing catalyst having the general formula of CpMLm1Y3-m, wherein Cp is a group having cyclopentadienyl bone; M is Ti, Zr or Hf; L1 represents a negative monovalent bidentate anion ligand in which the X1, X2 and N bonded on C atom are ligating atoms respectively with X1 being O, S, Se or Te and X2 being S, Se or Te; Y represents halogen atoms, C1˜C20 alkoxyl or C1˜C20 hydrocarbonyl-substituted amino etc; m is 1, 2 or 3. The catalytic system is investigated by adopting a series of negative monovalent bidentate anion ligands and demonstrated fairly high activity. CN 1151993A discloses a novel metallocene catalyst for the polymerization of ethylene, which adopts pyrrolyl or its derivatives as coordinate ligands, and exhibits high catalytic activity in combination with sesquiethyl. The produced polyethylene performed low molecular weight and narrow molecular weight distribution. For instance, at the reaction temperature of 50oC, under the ethylene pressure of 0.04 MPa, after 7 hours' reaction, dipyrrole titanium dichloride has the polymerization activity of 3.4×105 g polyethylene/molar titanium/hour, and the molecular weight distribution of the polyethylene is 1.47.